PIC18FXX20 Datasheet, PDF (328/366 Pages) Microchip Technology – 64/80-Pin High Performance 1 Mbit Enhanced FLASH Microcontrollers with A/D

PIC18FXX20
FIGURE 26-11:
RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER AND POWER-UP
TIMER TIMING
VDD
MCLR
Internal
POR
PWRT
Time-out
OSC
Time-out
Internal
RESET
Watchdog
Timer
Reset
33
32
I/O Pins
Note: Refer to Figure 26-6 for load conditions.
30
34
31
34
FIGURE 26-12: BROWN-OUT RESET TIMING
VDD
BVDD
35
VIRVST
Enable Internal Reference Voltage
Internal Reference Voltage stable
36
VBGAP = 1.2V
TABLE 26-11: RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER, POWER-UP TIMER
AND BROWN-OUT RESET REQUIREMENTS
Param.
No.
Symbol
Characteristic
Min
Typ
Max
Units
Conditions
30
TmcL MCLR Pulse Width (low)
2
—
—
µs
31
TWDT Watchdog Timer Time-out Period (No
7
18
33
ms
Postscaler)
32
TOST
Oscillation Start-up Timer Period
1024 TOSC — 1024 TOSC — TOSC = OSC1 period
33
TPWRT Power up Timer Period
28
72
132
ms
34
TIOZ
I/O high impedance from MCLR Low
—
2
—
µs
or Watchdog Timer Reset
35
TBOR Brown-out Reset Pulse Width
200
—
—
µs VDD ≤ BVDD (see D005)
36
TIVRST Time for Internal Reference
Voltage to become stable
—
20
50
µs
37
TLVD
Low Voltage Detect Pulse Width
200
—
—
µs VDD ≤ VLVD
DS39609A-page 326
Advance Information
 2003 Microchip Technology Inc.